Drop hammer safety device



Feb.5, 1952 Filed Nov. 20, 1946 G. E. BARNHARDTSON 5 Sheets-Sheet l "IllINVENTOR.

5, 1952 G. E. BARNHARDTSON 2,584,534

DROP HAMMER SAFETY DEVICE Filed Nov. 20, 1946 1 3 Sheets-Sheet 2 1 A i{/5 L INVENTOR.

@Qzaaagy DROP HAMMER SAFETY DEVICE Filed Nov. 20, 1946 5 Sheets-Sheet 5Patented Feb. 5, 1952 uNiTEo sTAT S PATENT bFFlCE DROP HAMMER, SAFETYDEVICE George E. Barnhardtson, North Providence, It. I. ApplicationNovember 20, 1946, Serial No. 711,093

Claims. 01. 192-129) The present invention relates to drop hammermachines operated byhydraulic pressure, and has particular reference wesafety device for use with pneumatic lift gravity drop hammers, powerpresses, foot presses and the like.

Theprincipal object of theinvention is to provide a pneumaticsafety'device which prevents inadvertent release of the hammer head, and inaddition operates a guard for throwing ,out the handsof the operatorbefore the hammer head descends.

. Another object of simple arrangement for a safety device which may bereadily applied to existing installations of pneumatic drop hammers,power presses, foot presses and the like.

Still another object of the invention is to provide a safety devicewhich is hydraulically operated in prior timed relation to the releaseof the hammer head, so that the safety provisions are operative untilthe hammer head is released.

, With the above and other objects and advantageous features in view,the invention consists of a novel arrangement of-parts more fullydisclosed in the detailed description following, in conjunction with theaccompanying drawings, and more specifically defined in the claimsappended thereto.

In the drawings:

.Fig. 1 is a front elevation of a standarddrop hammer installation inwhich the novel safety device is incorporated, parts being broken away;

Fig. 2 is a side view of Fig. 1;

Fig. 31s a detail view showing the spiral controls for the hammeroperation;

Fig. 4 is a detail section on the line 4-4 of Fig. 1, showing the safetyparts in safety position; and

Fig. 5 is a view similarto Fig. 4, showing the safety parts in hammerrelease position.

It has been found desirable to provide a safety device for a drophammer, which positively locks the hammer in raised position until bothhands of the operator are away from the anvil and are engaged inpressing dual valve controls to re lease the hammer head, whereupon thesafety lock is released and a hand guard sweep is simultaneously movedacross the face of the anvil. To this end I provide a control mechanismwhich may be attached to a drop hammer or press of standard type tofunction in timed relation to the the anvil to slidably carry the drophead l5, and

a yoke I6 is mounted on the upper end of the columns l3, I4 to carry apneumatic lift cylinder I! which is bolted to the central portion of theyoke and has a central lift rod l8 which is connected at its upper endto the cylinder piston, not shown, and at its lower end to the drop headl5.

the invention is to provide a The control of pressure air to andlfromthe lift cylinder 1'! is accomplished through a valve housing l9 whichincludes an operating control valve 20, and an inflow valve 2 Air underpressure is supplied to the valve housing I9 from a main pressure airconduit 22 through a reducing valve 23 and a main conduit 2%, and passesthrough the operating control valve 29 and the inflow valve 2| andthrough a passage in the yoke IE to the lift side of the piston in thelift cylinder l5. Air is exhausted from the cylinder ll through anexhaust passage in the yoke which leads through the operating control,valve 20 and an adjustable bleed valve 25 to atmosphere.

The operating control valve 20 is mechanically actuated by a rotatablymounted vertical rod 26, see Fig. 1, which has a spiral cam 21 securedat its lower portion with which a pin 28 at the lower end of the drophead l5 cooperates. The inflow valve 2| is mechanically controlled by arotatably.

mounted vertical rod 29 which has a spiral cam 30 secured at its upperportion for cooperation with a pin 3| at the upper end of the drop headWhen the drop head 15 is in its up position the inflow valve 2| is shutto the fiow of pressure air, but a by-pass, not shown, in the valvehousing, permits air under pressure to enter the lift cylinder and keepthe drop head up. When the drop head drops the upper head pin 3| turnsthe cam 30 and the rod29 to set the inflow valve 2| in open position,whereby pressure air may enter the lift cylinder through the operatingcontrol valve 20 when the lower head pin 28 turns the,

cam 2! and the rod 26. The drop head is released when the control valveis opened to exhaust, as hereinafter explained, the speed of drop beingcontrolled by the bleed valve 25, which may be manually set by turning avertical control rod 32 by means of a handle 33.

The control valve is turned to exhaust position by a hydraulic trip 34which is in a housing 35 at the right of the anvil, the pressure air foractuating the trip passing from the cylinderair supply through a conduit35 which extends around the anvil, and has a connection 3'! leading intothe housing 35; a manually operable shut-off valve 38 is mounted in theline and two spring pressed hand valves 39, 40 are also in the line andare, adapted to be manually depressed through hinged plates 4 42,whereby both hands of. the operator must be applied to release the drophead.

Referring now to Figs. 4 and 5, a-safety cylinder itis mounted at oneside onthe anvil and has a spring pressed plunger 44 which is leverconnected to a hub 45 keyed to a rotatable vertical rod 46,. A lookelement 41 is keyed to the rod 46 and isadapted to position a lockfinger 48 in the path of downward movement of the drop head to lock thedrop head in its up position, the hub 45 having an extension 49 to whichan anvil sweep 50 is connected The plunger is actuated by pressure airfrom a conduit 5| which passes through a valve housing 52 in which areciprocable valve 53 slides, he valve having a slot 54 to selectivelyopen an inlet passage 55 and an exhaust passage 56, the inlet passagereceiving pressure air through a connection 51. The valve 53 has ahinged valve rod 58 which has a'slotted end 59, and a hub 60 is keyed tothe control rod 29 and has an adjustable end bolt connection whichextends through the slotted valve rod end 59 to obtain a predeterminedtimed operation of the valve 53 with respect to the movement of thecontrol valve to exhaust position. WVhen the rod 29 is turned by thedrop head pin ,3! on (its upstroke the valve 53 is moved to open theexhaust passage 56 and thus causes locking movement of the lock element41. When the trip is actuated by manually pressing the valves 49, 40 toopen position, the rod 29 turns, the valve 53 is opened to entry ofpressure air which shifts the lock element 4'] out of the path ofdownward movement of the drop head and at the same time sweeps the anvilsweep 50 across the face of the anvil, and the control valve issimultaneously turned to exhaust, whereby the drop hammer drops, thelock element being mounted at .a distance from the drop head to providesufiicient clearance between the drop head and the lock finger. When thedrop head is lifted, the control rod moves to shift the valve 5s and thelock element moves to assume its normal lock position in the path ofdownward movement of the drop head.

The above described safety arrangement is thus simple in constructionand effective in operation, and may be readily adapted to standard drophammers and presses.

Although I have described a specific construc- .tional embodiment of myinvention, it is obvious that changes in the size, shape, andarrangement,

of the parts may be made to suit different types and styles of drophammers and presses, without departing from the spirit and the scope ofthe invention as defined in the appended claims.

I claim: I

1. A safety device for a drop hammer having an anvil, a drop head, andmechanism for lifting and for releasing the drop head, comprising a lockelement normally positioned in the path .of downward movement of thedrop head,

for preventing said downward movement and an anvil sweep adapted to moveacross the face of the anvil, and manually operative means forinitiating downward movement of the .drop head for shifting the lockelement out of the path of the drop head and for moving the anvil sweepacross the face of the anvil, and means .operative upon lifting movementof the drop head for shifting the lock element back into the path of thedrop head and for moving the anvil sweep back .to its original position.

,2, A safety device for a drop hammer having" an anvil, a drop head, andpressure actuated mechanism for lifting and for releasing the drop head,comprising a lock element normally Positioned in the path of downwardmovement of the drop head for preventing said downward movement, andmanually operative means for initiating downward movement of the drophead for shifting the lock element out of the path of the drop head, andmeans operative upon lifting movement of the drop head for shifting thelock element back into the path of the ,drop head, said means includinga cylinder having a pressure actuated piston and .mechanism connectingthe piston to the lock element.

:3. A :safety' device forafidrop hammer having an anvil, a drop head,and a pressure actuated mechanism for lifting and for releasing the drophead, comprising a lock element normallypositioned in the path ofdownward movement of the drop head for preventing said downward movementand an anvil sweep adapted to move across the face of the anvil, andmanually operative means for initiating downward movement of the drophead for shifting the lock element outof the path of the drop head and,for moving the anvil sweep across the face of the anvil, and meansoperative upon lifting movement of the drop head for shifting the lockelement back into the path of the drop head and for moving the anvilsweep back to its original position, said means including a cylinderhaving a pressure actuated piston and mechanism connecting the pistontothe lock element and the anvil sweep.

4. A safety device for a drop hammer having an anvil, a drop head, andpressure actuated mechanism for lifting and for releasing the drop head,comprising a lock element normally positioned in the path of downwardmovement of the drop head for preventing said downward movement, andmanually operative means for initiating downward movement of the drophead for shifting the lock element out of the path of the drop head, andmeans operative upon liftingmovement of the drop head for shifting theylook element back intothe path of the drop head, said means including acylinderhaving a pressure actuated piston, and ,a control valve operatedby the drop head, and mechanism 'connecting the piston to the lockelement.

5. Asafety device for a .drop hammer having an anvil, a drop head, and apressure actuated mechanism for lifting and for releasing thedrop head,mcomprising a lock element normally positioned in the path of downwardmovement of the drop head for preventing said downward movement and ananvil sweepadapted to move across the face of the anvil, and manuallyoperative means for initiating downward movement of the drop head forshifting the lock element out of the path of the drop head and formoving the anvil sweep across the face of the anvil, and means operativeupon lifting movement of the drop head for shifting the lock elementback into the path of the drop head-and for moving the anvil sweep backto its original position, said means including a cylinder having apressure actuated piston, a control valve operated by the drop head, andmechanism connecting the piston to the lock element and the anvil sweep.

. GEORGE E. 'BARNHARDTSON.

REFERENCES CITED The following-references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name .Date

1,082,685 Dyer Dec. 30, 1913 1,084,631 Hazel et a1. Jan. 20, 19141,18%,446 Hamilton May 23, 1916 1,196,764 Dicks Sept. 5, 1916 1,511,113Doersam Oct. 7, 1924 1,722,506 Sahlin'; July 30, 1929 2,240,630 StacyMay 6, 1941 2,246,021 Sturm et a1. "is" June 1'7, 1941 2,339,214Yanchenko Jan. 11, 1944 2,429,261 Ewaldson Oct. 21,1947'

